[hpsdr] Dumb question - HPSDR sound card

[Chris Albertson]

Me too.  I've been playing with GNU Radio and a sound card and
for audio frequencies. it works well.  But I'm never going to be able
get anything but narrow band modes down my M-Audio "audiophile"
sound card.

I followed up on the post made here yesterday.  That said basically
"Look at this"
http://www.analog.com/en/prod/0,2877,AD9874,00.html

Well I DID look at it.  First off, Wow! For medium bandwidths this
is perfect.  Second, it's only $15.  Third, it's SO much
better than a sound card.  It's the entire SDR front end on a chip.
Also it is quite easy to interface as it uses that three wire serial
SPI standard.  Unlike big parallel data buses SPI can us a long,
thin, cheap cable.  

I would not even consider using a sound card-style chip when I could
get a A/D converter with megahertz class bandwidth, VFO, mixer, AGC and
so on all on one cheap chip.
One "big thing" is that is has the decimater on-chip too.  The GNU
Radio and HPSDR people are using FPGA chips to do this. Why bother if
you
can buy a programmable decimater, mixer, A to D and so on for $15.

One more thing.  The application notes describe how to use multiple
AD9874 chips, each connected it's own antenna  -- A diversity receiver.


--- Darrell Bellerive <va7to at yahoo.ca> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> I too have been thinking along similar lines. I thought it would be
> nice to 
> have a high performance "sound card" for use as an audio scope and
> audio 
> spectrum analyzer.
> 
> I have a M-audio Audiophile 2496 PCI card in my computer, but find
> that it 
> is still not a good as I would like in a sound card. Too noisy and 
> overloads too easily. Maybe I expect to much, though.
> 
> I think that an external card would be ideal as it gets away from all
> that 
> noise floating around inside the PC.
> 
> I think this would be a great spinoff of HPSDR technology.
> 
> Darrell
> VA7TO
> 
> 
> On April 4, 2007 08:10 am, Terry Fox wrote:
> > ***** High Performance Software Defined Radio Discussion List *****
> >
> > This may sound like a divergent path, but...
> >
> > There is a consistent problem with sound cards used with SoftRocks
> and
> > other simple SDR hardware.  Especially laptops.  I realize the work
> here
> > on Janus & Ozy will create a high-quality converter (I have one set
> on
> > order), but there may be room for a simpler project as well.
> >
> > How difficult would it be to take the A/D & D/A and interface them
> to an
> > FPGA or other USB/firewire interface, all on a single, low-cost
> board? 
> > For those not interested in spending over $350 for Atlas, Janus,
> Ozy (or
> > expensive commercial USB/firewire solutions), this one-board
> solution
> > would be attractive.  I think it would need to cost less than $100.
> >
> > This is an ongoing issue that will not go away for a while.  I
> realize it
> > may "undercut" the Janus/Ozy/Atlas somewhat.  I also realize that
> there
> > are many, many sound cards out there, but all are less than optimum
> or
> > expensive, again especially for laptop use.
> >
> > The cheap PCM2900 boards got me thinking about this potential
> project.
> > Interfacing a better A/D and D/A to USB in such a way that Windows
> and
> > Linux will find them is all that is required.
> >
> > Horton comes the closest to this, but it has the QSD and no D/A, I
> > believe.
> >
> > Spending $400 for a firewire audio card to use a $13 SoftRock Lite
> with a
> > laptop doesn't make sense.  Spending $75 to $100 might.  I believe
> that a
> > project like this would do a lot to simplify and therefore further
> SDR
> > acceptance in the amateur community.
> >
> > Just a thought.
> > Terry
> 
> -- 
> Darrell Bellerive
> Amateur Radio Stations VA7TO and VE7CLA
> Grand Forks, British Columbia, Canada
> _______________________________________________
> HPSDR Discussion List
> To post msg: hpsdr at hpsdr.org
> Subscription help:
> http://lists.hpsdr.org/listinfo.cgi/hpsdr-hpsdr.org
> HPSDR web page: http://hpsdr.org
> Archives: http://lists.hpsdr.org/pipermail/hpsdr-hpsdr.org/
> 


Chris Albertson
  Home:   310-376-1029  chrisalbertson90278 at yahoo.com
  Office: 310-336-5189  Christopher.J.Albertson at aero.org


 
____________________________________________________________________________________
Looking for earth-friendly autos? 
Browse Top Cars by "Green Rating" at Yahoo! Autos' Green Center.
http://autos.yahoo.com/green_center/

 1175707492.0